Freeway driving — Idaho Permit Test

Where designated and as weather permits, vehicles may travel at speeds up to 80 miles per hour on rural interstates and up to 65 on urban interstate highways, unless otherwise posted.

The two numbers are different because a rural interstate has fewer exits and fewer places for traffic to join.

vehicles may travel at speeds up to 80 miles per hour on rural interstates, and up to 65 on urban interstate highways, unless otherwise posted

Freeways are usually safer than other roads because they have one-way traffic, a limited number of entrances and other special safety features, but they can encourage boredom and fatigue.

Nothing comes the other way and nothing crosses, so the danger moves from the road to the driver.

However, they can encourage boredom and fatigue that the driver must guard against

A freeway entrance usually has three parts: an entrance ramp, an acceleration lane and a merging area.

Each part has a job, and a driver who is still at ramp speed in the merging area has skipped the middle one.

Freeway entrances usually have three basic parts: an entrance ramp, an acceleration lane, and a merging area

On the acceleration lane you should accelerate to the speed of freeway traffic so you can blend in smoothly, and in the merging area you blend into the flow in the freeway's outside lane.

Joining slowly means everyone already there has to brake, which is how a line of traffic starts at an on-ramp.

The ramp will straighten out into the acceleration lane where you should accelerate to the speed of freeway traffic

You must yield to the traffic already on the highway when you merge.

The traffic already there has nowhere to go, and a car forcing into it makes everybody brake at once.

Remember, you must yield to the traffic already on the highway

If you enter the wrong freeway entrance by mistake, never try to back up or turn around through the median. Freeway median crossovers are for highway maintenance or emergency vehicles only, and it is illegal for any other vehicle to use them.

A car crossing the median arrives in the fast lane of the other carriageway, head on to everything in it.

Freeway median crossovers are for highway maintenance or emergency vehicle use only

Once on the ramp, check the traffic around you and on the freeway, signal, and begin looking over your left shoulder for a gap large enough for your vehicle without crowding anyone.

The gap has to be big enough to arrive in, not just to squeeze into.

Signal and begin looking over your left shoulder for a gap in the traffic large enough for your vehicle to fit into without crowding anyone.

If you need to get off the freeway or change direction, wait until the next exit to do so.

There is no other way off, and everything that looks like one is either a maintenance crossover or a ditch.

If you need to get off the freeway or change directions, wait until the next exit to do so

Where the ramp, acceleration lane or merging area is shorter than normal, or traffic is heavy, you may have to slow down before reaching the end of the acceleration lane.

The acceleration lane runs out whether or not a gap has appeared, and arriving at the end at speed leaves nowhere to go.

If there's no opening, you may have to slow down before reaching the end of the acceleration lane

If a short acceleration lane and heavy traffic force you to stop, leave enough room ahead so you can accelerate up to freeway speed as you merge.

A car starting from a standstill against the bumper in front cannot reach freeway speed before the lane ends.

be sure to leave enough room ahead so you can accelerate up to the speed of freeway traffic as you merge

Most of the time you should drive in the far right or center lane of a freeway. The left lane is for higher-speed traffic and passing.

A car cruising in the left lane forces faster traffic to pass on the right, which is where nobody is looking for it.

The left lane is for higher-speed traffic and passing

During rush hours you should avoid the right lane to leave room for drivers entering the freeway.

The right lane is where every on-ramp arrives, and in heavy traffic that is where the merging goes wrong.

During rush hours, you should avoid the right lane to allow room for drivers entering the freeway

On a freeway the five-second signal is required before leaving it as well as before changing lanes.

Traffic behind reads the exit the same way it reads a lane change, and an unsignaled exit is a car slowing for no visible reason.

Always signal for at least five seconds before making a lane change or exiting a freeway

It is illegal to drive across a barrier or unpaved strip separating two halves of a roadway, except at an authorized opening or crossover.

The strip is there to keep the two directions apart, and crossing it undoes the only thing protecting both.

It's illegal to drive across a barrier or unpaved strip that separates two halves of a roadway, except at an authorized opening or crossover

About half a mile before your exit, if you are not already in the correct lane, signal and move into the lane nearest the exit, then move into the deceleration lane to slow down without interrupting the flow of traffic.

Slowing down in the through lane makes everyone behind brake, which is how a freeway backs up at an exit.

about a half mile before the exit, signal and move into the lane nearest the exit

An exit speed may be posted, and you should adjust your speed accordingly as you drive through the ramp.

The ramp is built for a much lower speed than the freeway, and a car arriving at freeway speed leaves the road on the curve.

An exit speed may be posted. Adjust your speed accordingly as you drive through the ramp

As you leave the ramp and enter another road you may be in more complicated and dangerous traffic than on the freeway, so be alert and adjust to the new conditions and slower speeds.

After an hour at 75 everything feels slow, and 45 in town is the speed a driver most often misjudges.

you may be driving in more complicated, dangerous traffic than on the freeway

Before starting a long freeway trip make a travel plan, planning for food, rest and fuel stops, and let someone know your route, how long you will be gone and when to expect you back.

If something goes wrong on a remote stretch, the plan is what tells anyone where to start looking.

Let someone know your travel plans, your route of travel, the length of time you will be gone and when to expect you back

If you cannot or do not want to drive at the posted speed on a freeway, choose another kind of road to travel.

A car far below the speed of the traffic around it is an obstacle, and freeways have no room for one.

If you can't or don't want to drive at the posted speed on a freeway, choose another kind of road to travel

What is the maximum speed on an Idaho urban interstate highway where designated?

65 miles per hour. The two numbers are different because a rural interstate has fewer exits and fewer places for traffic to join. July 2026 Idaho Driver's Handbook, p.83: “vehicles may travel at speeds up to 80 miles per hour on rural interstates, and up to 65 on urban interstate highways, unless otherwise posted”